1. Field of the Invention
The subject matter of this invention is identified in the claims.
In particular, the subject matter of this invention concerns a method for the transformation of cis- and trans-cyclododecene oxide into cyclododecanone using catalytically activated hydrogen in the presence of a copper catalyst under the reaction conditions that will be described in more detail below, which leads to the formation of the intermediate products cyclododecen-3-ol and cyclododecen-3-one and of the by-product cyclododecene.
2. Description of the Related Art
Cyclododecanone is an intermediate product that forms in the course of the most frequently applied industrial method for the production of laurinlactam. Cyclododecanone can be obtained in various ways from the C.sub.12 precursor cyclodoceda-1,5,9-triene. The only cyclododecanone synthesis which, as far as we are aware, is presently carried out comprises the catalytic hydrogenation of cyclododeca-1,5,9-triene to form cyclododecane, the oxidation of the cyclododecane by air to form mainly cyclododecanol and fluctuating quantities of cyclododecanone, and the subsequent catalytic dehydrogenation of the 12-ring alcohol to form the ketone.
In addition to this reaction sequence, the patent literature describes other methods which use cyclododeca-1,5,9-triene as the starting material and lead more or less directly to cyclododecanone. Thus, according to DE-AS 1058987 and the German Patent Specification No. DE-PS-1075601, cyclododecanone is produced by hydrogenating the cyclododecatriene oxide (=epoxycyclododecadiene) that was obtained by epoxidation from cyclododeca-1,5,9-triene to form cyclododecene oxide (=epoxycyclododecane) and the latter is subsequently rearranged to form cyclododecanone. However, this method has the drawback that the catalytic hydrogenation of cyclododecatriene oxide to form cyclododecene oxide does not have a sufficiently high selectivity. During this process, considerable quantities (approximately 10 wt %) of cyclododecanol and cyclododecane (approximately 5 wt %) form as by-products, both of which have to be discarded.
The method proposed in the patent SU 513966 appears to be especially simple in that it provides for a one-step synthesis of cyclododecanone from cyclododecatriene oxide. For this purpose, the unsaturated epoxide is hydrogenated in the presence of a nickel-aluminum-titanium catalyst. However, again, by-products that cannot be utilized for any other purposes form along with the cyclododecanol and the cyclododecane.
The inadequate selectivity of these two syntheses by way of cyclododecatriene oxide is apparently attributable to the fact that under the comparatively drastic reaction conditions necessary to hydrogenate the C--C double bond, the epoxide function triggers several secondary reactions at the same time.